Abstract: Residue return can provide nutrients for crops due to residue mineralization,thereby reducing the application of chemical fertilizers.Investigations on the mineralization of residue nitrogen (N) in soil,the supply capability of residue N to crops,and the use efficiency of residue N by crop plants are essential to assess the gain of residue return in agricultural systems.We reviewed the effect of residue return on nitrogen cycling and nitrogen fixation in legumes,and the crop utilization of residue N.The application of ¹⁵N labeling technique in the studies on the turnover of residue N was also addressed.It is essential to further study the turnover of residue N and crop use efficiency of residue N in typical soils,especially the association of symbiotic N fixation with the utilization of residue N.The rhizospheric effect on the mineralization of residue N would be the most interesting aspect in the mechanisms of the utilization of residue N.